SOLUTION: Jean is three times as old as her sister. In 6 years time she will be twice as old as her sister how old is jean

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Question 1032946: Jean is three times as old as her sister. In 6 years time she will be twice as old as her sister how old is jean
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +a+ = Jean's age now
Let +b+ = her sister's age now
----------------------------
(1) +a+=+3b+
(2) +a+%2B+6+=+2%2A%28+b+%2B+6+%29+
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Substitute (1) into (2)
(2) +3b+%2B+6+=+2%2A%28+b+%2B+6+%29+
(2) +3b+%2B+6+=+2b+%2B+12+
(2) +b+=+6+
and
(1) +a+=+3b+
(1) +a+=+3%2A6+
(1) +a+=+18+
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Jean is 18
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check:
(2) +a+%2B+6+=+2%2A%28+b+%2B+6+%29+
(2) +18+%2B+6+=+2%2A%28+6+%2B+6+%29+
(2) +24+=+2%2A12+
(2) +24+=+24+
OK